R/init.R

In netique/buildr: Organize & Run Build Scripts Comfortably

#' Discover Build Scripts & Create Makefile
#'
#' \code{init()} looks for \code{.R} scripts in a project root (current working
#' directory) that contain a specified prefix and separator. Then, it creates a
#' \code{Makefile} with rules describing how to run discovered scripts.
#'
#' The build script names should all follow a common pattern that is both human
#' and machine readable. Filename should incorporate a prefix ("build" by
#' default) and the "body" describing what the given script builds. Those two
#' essential parts are separated by underscore (i.e. "_")  by default as it
#' helps with the readability. Both parts are configurable (see below), but we
#' encourage you not to make any changes. Do not forget that build scripts are
#' matched for a prefix and separator concatenated together, so the script named
#' "build.R" won't be recognized, as it doesn't begin with "build_". Follow the
#' example below on how to include "build.R".
#'
#' @param prefix \emph{Character}. Prefix that solicited build scripts have in
#'   common. It is trimmed and stripped in the list of \code{Makefile} targets
#'   because of redundancy. Default to "build".
#' @param sep \emph{Character}. Separator between \code{prefix} and "body" of a
#'   build script filename. It is also stripped in the list of \code{Makefile}
#'   targets because of redundancy. Default to underscore (i.e. "_").
#' @param path \emph{Character}. Path being searched. Default to the project
#'   root (i.e. ".", the current working directory, call \code{getwd()} to print
#'   it). See \code{\link{list.files}} for more details on the topic.
#' @param ignore_case \emph{Logical}. Should the search be case-sensitive?
#'   Default to FALSE.
#' @param command_args \emph{Single character}. Command argument(s) to include
#'   after the recipe call. Command argument can be picked up by your script
#'   with \code{\link{commandArgs}}. See
#'   \code{vignette("know_your_buildr")} for more details. Empty string by
#'   default (not in use).
#'
#' @family functions from buildr trinity
#' @keywords file utilities misc
#' @noMd
#'
#' @return No return value. Called for side effects.
#'
#' @author Jan Netik
#'
#' @importFrom rstudioapi executeCommand
#' @importFrom readr write_lines
#' @importFrom stringr str_extract str_trim
#' @importFrom tibble tibble
#' @importFrom magrittr %>%
#' @importFrom glue glue glue_data
#' @importFrom usethis ui_done ui_field ui_code ui_value ui_stop ui_path
#'
#' @examples
#' \dontrun{
#' # if you stick with the defaults, run:
#' init()
#'
#' # if you want to include "build.R",
#' # you have to tell {buildr} to
#' # use an empty separator, like:
#' init(sep = "")
#' }
#' @export
init <- function(prefix = "build", sep = "_", path = ".", ignore_case = TRUE, command_args = "") {
  pattern <- paste0("^", prefix, sep, ".*\\.R$")

  files <- list.files(path, pattern, ignore.case = ignore_case)

  if (length(files) == 0) {
    ui_stop(c(
      "{ui_field('{buildr}')} has not discovered any build scripts. Have you created them yet?",
      "If so, try to call {ui_code('init()')} again with different {ui_field('prefix')} and/or {ui_field('sep')} arguments."
    ))
  }

  rules <- tibble(
    rule = file_to_target(files, prefix, sep),
    recipe = glue("@Rscript -e 'source(\"{recipe_core}\")'",
      recipe_core = files
    ),
    command_args = ifelse(nzchar(command_args),
      paste0(" ", command_args),
      command_args
    )
  )

  rules %>%
    glue_data("{rule}:\n\t{recipe}{command_args}", .trim = FALSE) %>%
    write_lines("Makefile")

  ui_done(c(
    "{ui_field('{buildr}')} has discovered following build script(s):",
    "{ui_value({rules$rule})}. Proceed with {ui_code('aim()')}."
  ))
}